The present invention relates to radar systems, and more particularly to maximum likelihood estimation and range only initialization methods for use in multislope linear frequency modulated waveform radar systems.
Current multislope linear frequency modulated waveform radar processing techniques are limited to resolving to small number of targets (not more than 4) without a significant increase in ghosts (false alarms). Several techniques currently exist for resolving multiple targets in a radar using a linear frequency modulated waveform. One computes a target range measurement for every possible combination of returns, and another provides range and doppler measurements of the target separately.
Computing all possible combinations needed for target detection requires very large amount of signal processing throughput and yields a large number of ghosts. The requirement of high throughput results in an expensive radar system, and a large number of ghosts creates hazardous conditions. With a system providing range measurement only, the velocity estimate is derived from differencing consecutive range measurements or using filtering. In either case, these estimates require very accurate range measurements and introduce unacceptable latencies.
For automobile applications, such as adaptive cruise control systems, for example, large latency introduces additional risks in automobile "cut-in" or hazardous situations. A system that separately measures range and doppler cannot guarantee that the range and doppler measurements are derived from the same target. Again, this results in an adaptive cruise control system having a very slow response time.
Consequently, it is an objective of the present invention to provide for a maximum likelihood estimation and range only initialization methods for use in multislope linear frequency modulated waveform radar systems that provides for the resolution of a large number of target returns without extensive signal processing, and without creating a significant number of false alarms (ghosts).